Investments (Gains and (Losses) for Equity Securities) (Details) - Southern California Edison - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Investment Holdings [Line Items]
Gross realized gains	$ 39	$ 23
Gross realized loss	(2)	0
Net unrealized (losses) gains for equity securities	$ (376)	$ 168

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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